Measurement of the amount of liquid and vapour created by an electric arc on an electrode – case of Ag and AgSnO₂ electrodes

Laboratoire de Génie Électrique de Paris, Centre National de la Recherche Scientifique (UMR 8507), SUPELEC, University of Paris 6 et Paris 11, 11 rue Joliot Curie, Plateau de Moulon, 91192 Gif-sur-Yvette, France

^a e-mail: teste@lgep.supelec.fr

Received: 18 October 2010
Accepted: 3 March 2011
Published online: 21 July 2011

Abstract

In this paper an original experimental device is presented. It allowed to obtain, for the first time, the total amount of liquid and vapour of metal created on the electrode surface by a non stationary electric arc (600 A/20 ms) burning in air at atmospheric pressure. The results are presented for two different materials Ag and AgSnO₂ and for electrode gap values in the range 1–10 mm. The amount of liquid and vapour created under the arc action is compared with usual erosion rate in the same experimental conditions. In the case of Ag electrodes the amount of liquid metal created on the anode may be 3 to 5 times higher than on the cathode although the usual erosion rates are more important at the cathode. For the anode, the usual erosion may represent a very low percentage (<10%) of the total amount of metal liquid created showing then that a very small part of the liquid created during the arc is ejected. In the case of AgSnO₂ electrodes the amount of liquid metal is smaller. The usual erosion rates at the cathode are higher than for the anode and the usual erosion represent 10 to 50% of the amount of liquid and vapour created.